Key Biodiversity Significant numbers of wintering waterbirds (more than 20,000 individuals) and raptors occur in some years. Species of global conservation concern that do not meet IBA criteria: Haliaeetus albicilla (max. 5, non-breeding). Sterna hirundo, S. albifrons and Alcedo atthis, listed on Annex I of the EC Birds Directive, breed at the site.